Chlorination of 3-hydroxybenzaldehyde



Patented Sept. 30, 193i) unite s.

m PZMENT QFF E [Don wrrssELL AND FREDERICK KRANZ, F BUFFALO, NEW YORK, assreuonsmo ima rounneuimun & CHEMICAL COMPANY, ruo.,euu1sw YQRK, N. YJ, A 00R- roar-arrow or NEW our;

oHLoR-iuA'rmn o1" a-ritznuoxriznuzamnriynn N0 Drawing.

3hydroxybenzaldehyde, namely, 2-chlor-3- hydroxybenzaldehyde., The invention also includes improvements n the controlcf the u'chlorination process whereby the (i6S119t .chlorination;products may .be obtained in substantially v maximum yields.

The presentinvention is. based upon the.

if liscoyerythatthe chlorination of -l-hydroxyaib enzaldehyde can be] carried out in stages,

and i with production of substantially maximum yields of the monochlon, dichlor-, or 'trichlor- [derivatives of 3-hydroxybenzaldehyde bypassingchlorine into a warm glacial 0 acetic acid 1 solution of 3-hydroxybenzaldehyde. lT-he invention also includes an im-.

proved method of controlling the process, whereby. chlor nation products 01 the desired degree ofchlorination can be obtained-in sub-' stantially the, maximum yield and with a minimum, production of admixed higher and lower chlorinationproducts. I

1 It is known; that .S-hydroztybsnsaldedyde canbe chlorinated by the action of chlorine upon awarin solution oi 3-hydroxyhenzaldehyde; iuglacial acetic acid, but so far as we are-aware, di chlor and trichlor-3-hydroxypecia-lly} dichlor -hydroxybenzaldehyde, can

yields.

-hydroxybenzaldehyde in arm glacial acetic 1 acid :solutioncan be soregulated and con trolled that a :product consisting essentially of m onochlors3 hydroxybenzaldehyde can be -higherchlorinationproducts; and that the bentaldehyde are the only products thatliave been obtainedin this Way. According to. the present invention, however, the lower as well -i-asithe higher chlorinationv products, and eslVeyhave found that chlorination of 3-,

produced. with a minimum production of Application filed November 22, 1921. Serial. No, 5173076.

ess, the tric'hlor-8-hydronybenzaldehyde can also be produced as the principal product with a ininimuinproduction oi by-g iroducts rich, for example, "as aldehyde-trichlorquinonedichloriddfetc.

WVe have found that, when the chlorination of 3hydroxybenzaldehyde is so regulated that monochlor 3hydroxybenzaldehyde is the principal chlorination product, the mono? 1 i 0 a l l V cnlor-dhydroxybenzaldehyde which is formed consists principally of' a mixture of 2- 'chlor-3-hydroxybenzaldehyde and Spiller-3- h'ydroxybenzaldehyde. The 2-chlor-3 -h ydroxy benzaldehyde, when, purified, has a melting po nt'oi about 139139;5 and the 6-chlor-8 hydrOXybenZaldehyde, when purifiechhas a melting point of aboutll().5 11 15 C. The former ofthese two substances in so far as welare aware, has not-beenfheie tofore produced, and we accordingly regard it as new. The mixture 05 the two compounds has pronouncedsternutatory properties. Itmay serve as anyintermediate, i'n'the I preparation of other chemical compounds as dye stufiis. 1

The d1chlo1'-3,-liyd roxybenzaldehyde which is produced consists chiefly of 2.6-dichlor-3- hydroxybenzaldeliydc, and, when purified, melts at about 142-1422 6.; the ti'ichler-3- hydroxybenzaldehyde which is fOl'lllQQllS the 2.4.6-trichlor-3-hyd1oxybensaldehyde, and, when purified, melts at about'l15.5-1l6l5 G.

We havefdiscovered that,'in the chlorination of '3-hydroxybenzaldehyde in (glacial acetic acid solution by the action of chlorine, the relative stage or degree of chlorination .may be approximately. determined by noting the temperature at which the solution is just saturated with respect to the product or pr oducts which may be present or are formed during-the course of the reaction. This temperature is denoted as the saturationtemperature. Within limits, for each definite concentration of the components which connarise the solution there is a temperature at which complete solution ust takes place. For example, one ,mol of 8-hydroxybenzaldehyde dissolved in approximately three and six-tenths inols of glacial acetic acid produces a saturated solution at afternperature of about v53" 0. Upon passing chlorine into thissolution, and as chlorination progresses, the temperature of saturation first falls to a minimum and then rises to a definite maximum, about 62 0., at which temperature a mixture or" the monochlor-S-hydrOxybenzaldehydes is present in maximum quantity. Upon continued chlorination, the saturation temperature again falls and then rises to another definite maximum, about 93 0., at which temperature dichlor-3-hydroxybenzaldehyde is present in greatest quantity. Upon further chlorination the temperature of saturation again falls to a minimum and again rises to a maximum, about 65 0., at

' a temperature of 6570 0., until crystals begin to separate. The temperature of the solution is then raised and maintained 'at 75-80 0., and the chlorination continued until enough chlorine has been taken up by the solution to correspond to the formation and maximum yield of dichlor-hydroxybenzaldehyde. This stage of chlorination is determined by removing a sample of the mixture, cooling the same with vigorous agitation until-crystals separate, and then care fully Warming with observation of the temperature until all of the crystals just disappear. WVhen chlorination has proceeded to such an extent that a test sample shows 93 0. as the temperature of disappearance of crystals, the chlorination is discontinued.

The chlorinated mixture is then poured into about three times its volumeof cold water, and the crystals which separate are filtered off and washed with water. The crude dichlor-hydroxybenzaldehyde thus obtained melts at about 125135 0. and may, if desired, be purified by recrystallizationfrom acetic acid.

Emample 2.240 parts of 3hydroxybenzaldehyde are dissolved in 860 parts of glacial acetic acid, and chlorine is passed into the agitated solution, which is maintained at a temperature of about 0., until crystals begin to separate out. The temperature of the solution is then raised and maintained at about -70 0., and the chlorination continued until a sample, cooled until crys tals appear, will again become clear upon raising the temperature to 78 0. The chlorinated mixture is then poured into about three times its volume of cold water, and the precipitate filtered off and washed. The crude dichlor-hydroxybenzaldehyde thus obtained melts at about 180135 0., and may bepurified, if desired, by recrystallization from acetic acid.

It will be noted that in the progressive chlorination of an acetic acid solution of 3-hydroxybenzaldehyde there are successively aroduced three maximum saturation temperatures, each representing in order of production the point at which monochlor-, dichlorand trichlorhydroxybenzaldehyde, respectively, is present in the largest amount. With other and different concentrations of the components comprising the acetic acid solution, the individual maximum saturhtion temperatures will vary, but in any case the point where the greatest amount of any one of the components is present will be that at whichthe maximum saturation temperature is shown in its proper sequence. careful preliminary pre-determination of the variousmaximum saturation temperatures for any given concentration will enable thereafter .the chlorination of such concentrations to be carried'out and controlled by means of such preedetermined maximum temperatures, and in this way one may obtain the maximum yields of either monochlor-, dichlorortrichlorhydroxybenzaldehyde as may be desired. 0f the three maxi mum saturation temperatures, the highest is that produced when di-chlorhydroxybenzaldehyde is present in greatest quantity.

It willthus be seen that the present inventionmakes possible the regulated chlorination of 3-hydroxybenzaldehyde and the production, as the principal products or the chlorination, of either the monochlor-E-hydroxybenzaldehydes, or the 2.6-diel1lor-"- hydroxybenzaldehyde, orthe trichlor-3-hydroxybenzaldehyde. In particular, the present invention makes possible the production of the 2.6-dich1or-3-hydroxybenzaldehyde or (if the 2 iiionochlor-3-hydroxybenzaldehydes, as the main products of the process. It will also be seen that the present invention provides a new and improved method of controlling the chlorination whereby the desired products can be produced with a mini mum production of other chlorination products;

We claim:

1. In the production of a halogenated deriva 'e of 3-hydroxybenzaldehyde by subjecting 3-hydroxybenzaldehyde in acetic acid solution to the action of a halogen, the improvement which comprises determining the saturation temperature of the reaction mixture from time to time and continuing the addition of the halogen until the saturation temperature of the reaction mixture rises to a maximum.

2. The method of producing a monohalodition of chlorine until the saturation temrivat ve of 3-hydroxybenzaldehyde by subgenated derivative of 3-hydroxyben zaldehyde which comprises introducmg a halogen into an acetic acid solution of 3-hydroxy benzaldehyde with heating, closely observing the saturation temperature throughout the rivative or 3hydroxybenzaldehyde by sub- :GCt'Jlig3-l1yCl1'OXylO6I]ZitltlfiliytlG in acetic acld solution to the action" of chlorine, the im provcment which comprises intermittently determining the saturation temperature of the reaction mixture and continuing the ad perature of the reaction mixture has reached the maximum value associated with the chlorinated derivative of 3-hydroxybenzaldehyde.

4L. In the production of chlorine derivatives of 3-hydroxybenzaldehyde by subjecting 3- hydroxybenzaldehyde in acetic acid to the action of chlorine, theimprovement which comprises observing the changes in at least one physical property of the reaction miX- ture throughout the chlorination and terminating the chlorination at approximately the point at which the acetic acid solution be-- comes just saturated at a predetermined-temperature with respect to a chlorine derivative.

5;' In the production of chlorine deriva-, tives of 3hydroxybenzaldehyde by subjecting 3-hydroxybenzaldehyde in acetic acid solution to the action of chlorine, the improvement which compriseslcontrolling the degree l.

6. In the production of the, chlorinated derivatives of 3-hydroxybenzaldehyde bysubmctmg Shydroxybenzaldehyde 1n FLCGJUC acid solution to the action of chlorine the improvement which comprises 1nterm1tte'ntly withdrawing test samples of the reaction mixture and continuing the chlorination until. the temperature at which the separated crystals of a test sample disappear on heating reaches substantially a miXimum point.

7. The process of producinga monochlor derivative of S-hydroxybenzaldehyde which comprises heating an acetic acid solution of S-hydroxybenzaldehyde and passing chlorine into the solution until an amount of chlorine has been taken up corresponding to a maximum yield of a inonochlor derivative.

8. The method of producing monochlor derivatives of 3-hydroxybenzaldehydewhich comprises heating an acetic acid solution of '3-hydroxybenzaldehyde, subjecting the solution to the action of chlorine, determining the saturation temperature of the reaction mixture from time to time anddiscontinuing the chlorination at substantiallythat point at Whichthe acetic acid solution becomes ust saturated at a predetermined temperature with-respect to the monochlor derivative.

9. As a new product, 2-chlor-3-hydroxybenzaldehyde having a melting. point oi about 139 to 139.5 C. V r

10. As a new product, a mixture of monochlorinated derivatives of 3-hydroxybenzal- .dehyde containing 2-chlor-3-hydroxybenzaldehyde and 6-chl0r-3-hydroxybenzaldehyde. 11. In the production of a chlorinated dejecting a solution of the 3-hydroxybenzaldehyde to the action of chlorine, the improvement which comprises intermittently determining the saturation temperature of the reaction mixture and terminating the .chlori-' nation when the saturation temperature: approximates the maximum valuefassociated with the chlorine derivative of 3-hydroxybenzaldehyde. v

1 In the production-of a halogenated de- "rivative of 3-hydroxybenzaldehyde by subjecting 8-hydroxybenzaldehyde in solution .to the action of a halogemthe improvement which comprises carefully observing changes in aproperty of the reaction mixture during the reaction and terminating the halogenation when the saturation temperature approximates the 'maximum value associated with a particular chlorine derivative of 3- hydroxybenzaldehyde as indicated by the observed changes in a property of the reaction mixture.

13. In the production of a halogenated tie-- rivative of 3-hydroXybenzaldehyde by sub ecting "3-hydroXybenzaldehyde in acetic acid solution to the action of a halogen, the

improvement which comprises maintaining the reaction temperature during the difierent stages of halogenatiolrat or above the saturation temperature of the reactionmixture. r

14. In the production of a halogenatedderivative of 3hydroxybenzaldehyde by subjecting 3-hydroxybenzaldehyde in acetic acid solution tothe action of halogen, the

improvement which comprises controlling.

the degree of halogenation by reference to the temperature of saturation of the solution.

'15. In the production of a chlorine de-.

rivative of 3-hydroxybenzaldehyde by subjecting 3-hydroxybenzaldehyde in acetic acid solution to the action of chlorine, the improvement which comprises controlling the degree of chlorination by reference to the temperature of saturation of the solution which corresponds to a maximum saturation temperature.

1(3. The method of producing 2.6-dichlor- 3-hydroxybenzaldehyde which comprises treating a solution of 3-hydroxyb'enzaldehyde in acetic acid, in the ratio of one mol of 3ehydroxybenzaldehyde to approximately three and six tenthsanols of acetic acid, with chlorine, intermittently withdrawing test samples of the reaction mixture and continu- -ingrthe chl'orinationuntil the temperature, 7 at which the separated crystals disappear on heating-a test sample, reaches substantially 17. The method of producing 2.6-dichlor- 3-hydroxybenzaldehyde which comprises treating a solution of 3-hydroxyhenzaldehyde in acetic acid, in the ratio of one mol of 3shydroxybenzaldehyde to approximately seven and two tenths mole of acetic acid, with chlorine, intermittently withdrawing test samples of the reaction mixture and continu ing the chlorination until the 'temperature,

at which the separated crystals disappear on heating a test sample, reaches substan- V tially 78 C. I a x18. The method of producing 2.6-dichlor- 3-hydroxybenzaldehyde which comprises treating a solution of 3-hydroXybenzalde-- hyde in acetic acid with chlorine until the temperature at which the separated crystals or" a test sample disappear on heating fall to a minimum then rises to a maximum, again'talls to aminimum and rises approximately to a second maximum, andthen discontinuing the chlorination.

19. The method of producing trichlor- 3-'hydroxyhenzaldehyde, which comprises treating a solution of 3-hydroxybenzaldehyde in acetic acid, in the ratio of one mol of 3-hydroxybenzaldehyde to approximately three and one-half mols of acetic acid, with chlorine, intermittently withdrawing test samples ot'the reactionmixturevand continuing the chlorination until the temperature at which separated crystals disappear on heating a test sample reaches substantially a maximum of about C. after having passed through a higher maximum of about 93 C.

20. As a new product, trichlor-8hydroxyloenzaldehyde.

In testimony whereof we aiiixour signatures. I v

DOISIW. BISSELL. FREDERICK KRANZ. 

